Although numerous studies have attempted to document the contribution of genetic factors to the etiology of congenital or early onset deafness, geneticists have have not yet attempted to apply these techniquers to the study of hearing loss present in adulthood. The proposed study will involve the collection of systematic family history and medical data from hearing impaired persons who are members of a national consumer organization for hearing impaired adults. In year 1 of the study 20,000 members of this organization will be contacted to complete a short survey to collect basic data on family and medical history. During year 2 of the study 2,000 of these individuals will be recontacted to complete a more extensive familyu and medical history questionnaire. These 2,000 individuals will include 1,000 with a positive family history of other hearing impaired members and 1,000 controls with no family histor of hearing loss. The statistical technique of nuclear segregation analysis will be used to estimate the proportion of genetic cases in the respondents from the group of 20,000 contacted during the first year. Complex segregation analysis techniques will be used to analyze data from the in-depth family and medical history collected during Year 2. These statistical studies will provide the basis for future complex genetic studies. In addition, these analyses willprovide valuable information for genetic counseling and will document the need for future molecular studies of various types of adult-onset or progressive types of hearing impairment.